Colour Processing in Adversarial Attacks on Face Liveness Systems

In the context of face recognition systems, liveness test is a binary classification task aiming at distinguishing between input images that come from real people’s faces and input images that come from photos or videos of those faces, and presented to the system’s camera by an attacker. In this paper, we train the state-of-the-art, general purpose deep neural network ResNet for liveness testing, and measure the effect on its performance of adversarial attacks based on the manipulation of the saturation component of the imposter images. Our findings suggest that higher saturation values in the imposter images lead to a decrease in the network’s performance. Next, we study the relationship between the proposed adversarial attacks and corresponding direct presentation attacks. Initial results on a small dataset of processed images which are then printed on paper or displayed on an LCD or a mobile phone screen, show that higher saturation values lead to higher values in the network’s loss function, indicating that these colour manipulation techniques can indeed be converted into enhanced presentation attacks

Thyroid phantom measurements in joint EURADOS-LLNL intercomparison exercise

International audienceThe European Radiation Dosimetry Group (EURADOS), in collaboration with Lawrence Livermore National Laboratory's (LLNL's) Thyroid Intercomparison Program (TRIP), conducted an intercomparison exercise consistent with the goals of EURADOS. In total, 35 in vivo radiobioassay facilities from 18 countries participated to evaluate the differences between the neck and thyroid phantoms specified in two standards issued by the American National Standards Institute. Radioiodine (125I and 131I) measurement results were compared to the traceable standard activity levels added to each phantom. Measurement data showed no statistically significant differences between normalized activity measurements of the thyroid phantom types (20 and 30 ml). Differences were noted between the laboratories that routinely participate in the radioiodine thyroid intercomparison program (TRIP participants) and laboratories that have not previously participated in TRIP. Evaluation of the reasons for these differences will require additional EURADOS-LLNL collaborations. Finally, the measurement data from this intercomparison was used with a designed intake scenario for intercomparison of dose evaluations. Results from the dose intercomparison will be presented in a subsequent article. © The Author 2017. Published by Oxford University Press. All rights reserved

Recognising Human-Object Interactions Using Attention-based LSTMs

Recognising Human-object interactions (HOIs) in videos is a challenge task especially when a human can interact with multiple objects. This paper attempts to solve the problem of HOIs by proposing a hierarchical framework that analyzes human-object interactions from a video sequence. The framework consists of LSTMs that firstly capture both human motion and temporal object information independently, followed by fusing these information through a bilinear layer to aggregate human-object features, which are then fed to a global deep LSTM to learn high-level information of HOIs. The proposed approach applies an attention mechanism to LSTMs in order to focus on important parts of human and object temporal information

Sulfur Dioxide variability in the Venus Atmosphere

International audienceRecent observations of sulfur oxides (SO2, SO, OCS, and H2SO4) in Venus’ mesosphere have generated controversy and great interest in the scientific community. These observations revealed unexpected spatial patterns and spatial/temporal variability that have not been satisfactorily explained by models. Particularly intriguing are the layer of enhanced gas- phase SO2 and SO in the upper mesosphere, and variability in the maximum observed SO2 abundance and the equator-to-pole SO2 abundance gradient, seemingly on multi-year cycles, that is not uniquely linked to local time variations. Sulfur oxide chemistry on Venus is closely linked to the global- scale cloud and haze layers, which are composed primarily of concentrated sulfuric acid. Consequently, sulfur oxide observations provide important insight into the ongoing chemical evolution of Venus’ atmosphere, atmospheric dynamics, and possible volcanism.Existing observations have been obtained using multiple platforms, observing techniques, and wavelengths. Each has its own unique strengths and limitations. Although there is strong agreement on some features, there are significant unresolved apparent disagreements among current observations and between observations and models. These apparent disagreements need to be analyzed and assessed carefully to synthesize a clear understanding of sulfur oxide chemistry on Venus. These investigations have been performed via 1) the comparison and validation of observations, from past missions, Venus Express, Earth-based telescopes, and the Earth-orbiting Hubble Space Telescope; and 2) modelling of the SO2 and sulfur-oxide family photochemistry. The current study has been carried out within the frame of the ISSI International Team entitled ‘SO2 variability in the Venus atmosphere’

Fuzzy promises: explicative definitions of brand promise delivery

This article clarifies the commonplace assumption that brands make promises by developing definitions of brand promise delivery. Distinguishing between clear and fuzzy brand promises, we develop definitions of what it is for a brand to deliver on fuzzy functional, symbolic, and experiential promises. We argue (a) that brands deliver fuzzy functional promises through encouraging and facilitating courses of actions that are conducive to the promised functionality, whereas (b) brands deliver fuzzy symbolic promises through encouraging and facilitating ways in which consumers can use brands as narrative material to communicate self-identity. Finally, (c) we propose that brands deliver fuzzy experiential promises through effectively motivating consumers to adopt and play a social role implicitly suggested and facilitated by the brand. A promise is an inherently ethical concept and the article finishes off with an in-depth discussion of fuzzy brand promises as two-way ethical commitments that put requirements on both brands and consumers